The present invention relates to a bifunctional earphone set, and more particularly relates to a compact earphone set which functions as a microphone as well as a receiver used for electroacoustic treatment of human voices.
Generally in the field of electroacoustic treatment of human voices, voices are collected directly from a human mouth using an electric pickup such as a microphone. In the case of this voice collection, however, the microphone is liable to pick up unnecessary ambient sounds in addition to human voices to be collected and mixing of such ambient sounds causes generation of harsh noises in voice reproduction.
In order to cut off such ambient sounds, it was proposed by the inventor in his earlier Japanese application Hei. 3-240194 to collect human voices through vibrations of the tympanic membrane of a speaker at generation of voices. That is, vibrations of the tympanic membrane is sensed by a compact ear set provided with a built-in pickup such as a microphone. Collection of voices within the ear of the speaker only well excludes mixing of ambient sounds.
In the case of this prior invention, the compact ear set functions as a microphone. However, a separate receiver has to be prepared for reception and electroacoustic conversion of transmitted electric signals which carry acoustic information.